Some will blame Google for the demise of JPEG XL, but I think that's a red herring. JPEG XL includes Google technologies such as Pik and Guetzli/Brunsli. Some of the JXL developers are Google employees. Google doesn't have a profit motive to promote one format over another. Their upper management most likely isn't even aware that JPEG XL exists. It also doesn't explain why Mozilla and Apple are favoring AVIF too.

Nonetheless, there's no question that JPEG XL was sabotaged. AVIF was enabled by default in Chrome the day it was implemented, JXL had to go through an experimental period. At some point, Mozilla developers were told to stop working on improving their JXL implementation and they couldn't even merge already developed patches.[1]

Google's justifications for the removal were baffling. They said there's "not enough interest" despite all the hype, all the major companies requesting JXL support.[2] They claimed JXL doesn't bring "sufficient benefits", despite the numerous advantages, such as lossless JPEG recompression. They published their flawed[3] benchmarks weeks after they made the decision to remove JPEG XL.

BTW, the removal happened immediately after Adobe announced they are supporting JPEG XL in one of their products. Almost as if they realized that JXL may be gaining too much support and it's time to pull the plug.

So who's behind this if not Google? To me, the most likely suspect is AOM, the Alliance for Open Media. The people who are involved in AOM also the ones who make the decisions in the browsers. What are their motives? I don't know, pettiness? Maybe they just want their format to win.

[1] - https://phabricator.services.mozilla.com/D119700#3977128

[2] - https://bugs.chromium.org/p/chromium/issues/detail?id=117805...

[3] - https://cloudinary.com/blog/contemplating-codec-comparisons